随机获取用户定义的字符串

此类需要使用之前讲到的IntegerWeightRandom类；

示例：

给定"a"赋予权重100，"b"的权重为50，则getNextString()时取"a"的概率要更大；

package org.xiazdong.util;/*给定字符串集合，设定每个字符串的权重，返回随机字符串*/public class StringRandom {private String[] datas;private IntegerWeightRandom random = new IntegerWeightRandom();public StringRandom(String[]datas){this.datas = datas;}public void setStringWeight(int weight,int idx){if(datas.length>idx)random.addWeightNumber(weight, idx);}public String getNextString(){int idx = random.getNextInt();return datas[idx];}}

测试类：

package test.org.xiazdong.util;import org.junit.Test;import org.xiazdong.util.StringRandom;import junit.framework.TestCase;public class StringRandomTest extends TestCase {@Testpublic void testGetNextString() {StringRandom random = new StringRandom(new String[] { "a", "b", "c" });random.setStringWeight(10, 0);random.setStringWeight(20, 1);random.setStringWeight(30, 2);for (int i = 0; i < 10; i++)System.out.println(random.getNextString());}}